Expelling charge ignition system

ABSTRACT

An ignition system for a rocket which allows ignition of an expelling stage, after a predetermined elapsed time, by the hot gases from the combustion chamber, thereby obviating the necessity of a separate fuze for the expelling stage. A valve separating the expelling charge stage from the hot gases of the combustion chamber is biased to an open position by a heavy coil spring. A collar of low melting point material holds the valve closed until it is melted by the gases of the combustion chamber.

United States Patent [191 Parker et a1.

[451 Dec. 24, 1974 EXPELLING CHARGE IGNITION SYSTEM Inventors: Leland L. Parker, Corona; Jerry 0. Jones, Ventura; Michael R. Osburn, Ridgecrest, all of Calif.

The United States of America as represented by the Secretary of the Navy, Washington, DC.

Filed: Oct. 23, 1973 Appl. No.: 408,784

Assignee:

US. Cl. 102/49.5, 102/37.l Int. Cl. F42b 15/10 Field of Search 102/49.3, 49.4, 49.5, 49.6,

References Cited UNITED STATES PATENTS 10/1953 Hansche 102/49.4

7/1963 Jansen et a1. 102/34.4

10/1963 Hagerty ..102/49.4 8/1964 LaPointe ..102/34.4

COIMBUSTION 3,397,638 8/1968 Gould l02/49.4

3,401,634 9/1968 Martin et al. 102/49.7

3,457,861 7/1969 Crockett 102/49.4 3,771,455 11/1973 Haas 102/49.4

Primary ExaminerBenjamin A. Borchelt Assistant Examiner-H. 1. Tudor Attorney, Agent, or FirmR. S. Sciascia; Roy Miller; Robert F. Beers [57] ABSTRACT An ignition system for a rocket which allows ignition of an expelling stage, after a predetermined elapsed time, by the hot gases from the combustion chamber,

thereby obviating the necessity of a separate fuze for the expelling stage. A valve separating the expelling charge stage from the hot gases of the combustion chamber is biased to an open position by a heavy coil spring. A collar of low melting point material holds the valve closed until it is melted by the gases of the combustion chamber.

2' Claims, 1 Drawing Figure l2 l4 l6 15 25 23 18 I9 24 32 27 EXPELLING CHARGE IGNITION SYSTEM BACKGROUND OF THE INVENTION 1. The present invention relates generally to an apparatus for use with a rocket r missile to cause an expulsion of a warhead or payload from the main body at the cessation of powered rocket flight.

2. In many applications, modern rockets or missiles need a simple effective apparatus that would permit automatic dispensing of objects carried by the missile at a predetermined time during its flight or path of travel. For example, it may be desirable in certain types of rockets to cause the nose of the rocket to separate from its body. If an expelling charge is used to cause separation it is usually ignited by a fuzing device. These fuzes may be a radar type or mechanical type designed to operate after a desired predetermined delay time. Mechanizations of this type are usually expensive and bulky. In addition, fuzing devices of this type usually required some sort of safing mechanism to prevent premature firing of the fuze.

SUMMARY OF THE INVENTION The present invention accomplishes the expulsion of a payload from a missile or rocket by providing an ignition apparatus for any desired rocket stage after propulsion stage. The ignition apparatus ignites later rocket stages by means of the hot gases from the prior stage. A valve biased by means of a spring to an open position separates the ignited stage from the unignited stage and is held closed by means of a heat sensitive collar. The temperature of the hot gases melts the collar and actuation of the valve to its open position occurs whenever the pressure in the ignited stage is less than the force of the spring. Opening of the valve allows hot gases to reach the unignited stage.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE is a cross-sectional view of the invention taken along the longitudinal axis.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing the rocket container 11 holds rocket propulsion fuel within the combustion chamber. A grain immobilizing spring 13 and associated combustion pressure plate 12 are affixed adjacent one end of container 11.

A payload compartment having a nose section 28 is attached to compartment body 24 to form a closed portion that may be used to carry explosives or deployable objects intended for release at the end of powered rocket flight.- Body 24 is releasably attached to container 11 by means of a stepped portion 23 and associated parts such as ring 25 and annular member 16. Spring 13 abuts annular member 16 holding body 24 in position at mating surface 32. An obturator material provides a seal between the end of body 24 and annular member 16.

The end portion of body 24 that fits within container 11 is formed with a multistepp'ed chamber. Positioned within this chamber is valve assembly 10. A round valve plug 14 made from heat resistant material, or the like is formed with a reduced diameter portion at one end'and a cavity at its other end. Plug 14 is mounted concentric and in spaced relationship with body 24. Spring 19 fits within the cavity to supply a force causing plug 14 to move away from the end of body 24. This allows valve 10 to open by disengagement of the plug surface at 33 from end surface of body 24.

A restraining collar 17 constructed from heat sensitive material fits over the reduced diameter portion of plug 14 and engages plug 14 to hold valve 10 in a closed position. Collar 17 is held fixed in this position by means of machine bolts 18.

An expelling charge 26 is molded in one end of body 24 adjacent valve 10. A double wall 31 and 32 encloses charge 26. Between walls 31 and 32 is an amount of absorbing shock material 29. An ignition mixture 27 for ignition of charge 26 closes an inlet hole through the end wall of body 24.

In operation the missile or rocket is propelled by burning of propellant fuel in a combustion chamber to cause the rocket to travel along a predetermined path or trajectory to deliver objects carried in the compartment formed by nose 28 and body 24. A valve 10 separates body 11 from expelling charge 26. During initial rocket flight valve 10 is held closed by means of collar 17. Hot gases from combustion chamber 11 cannot, travel to expelling charge 26 because valve 10 is closed by means of plug 14.

Burning of the rocket fuel produces high temperatures and high pressures within container 11. The heat of combustioncauses collar 17 to soften, melt or burn. This releases the restraining force against compressed spring 19 and allows opening of valve 10 whenever the pressure due to combustion of the propellant fuel drops. The pressure will remain sufficiently high to hold plug 14 against spring 19 until the grain combustion in chamber 11 nears completion. As the pressure recedes to a point where pressure against external surfaces of plug 14 can no longer keep spring 19 compressed, spring 19 will thrust plug 14 into the combustion chamber allowing hot gases to flow through passageway 21 into body 24 by means of the hole in the end wall of body 24.

The gases will impingeagainst ignition mixture 27 causing it to ignite and thus igniting expelling charge 26. The force from expelling charge 26 pushes shock reducing material 29 and walls 31 and 32 against objects carried within compartment 24 causing nose cone 28 to break away dispensing the objects within the compartment, such as a fleshette bundle or the like. The release of the objects will be concurrent with the time of final thrust of the rocket motor thus allowing deployment of the payload of the compartment at its maximum velocity.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore .to be understood that within the scope of the appended claims, the invention may be practiced otherwise than specifically described.

What is claimed is:

1. A rocket carrying a payload for ejectment at a predetermined point along its trajectory comprising:

a combustion chamber containing rocket propulsion fuel for propelling said rocket along a fixed path;

a compartment attached to said chamber having one 'end nearest said combustion chamber filled with an explosive charge for supplying a rapid expanding force;

shock reducing material positioned adjacent and in contact with said explosive charge for completely enclosing said explosive charge within an end portion of said chamber;

communicating passageway concentric with said compartment and said combustion chamber;

a circular plug member having a reduced diameter portion at one end to form a shoulder and a cavity at its other end, said plug member positioned between said chamber and said compartment and operable to open and close said communication passageway;

a spring housed partially within the cavity in said circular plug and compressed in its closed position; and

heat sensitive restraining collar fixably secured to said compartment and said plug at its reduced diameter portion for holding said plug member in a position to close said passageway; whereby the completed burning of the propulsion fuel in the combustion chamber causes hot gases to impinge upon the restraining collar allowing the passage of hot gases through the passageway to ignite the expelling charge to forcibly eject the payload from the compartment after the spring pressure overcomes the combustion chamber pressure. 2. The rocket of claim 1 wherein said passageway is formed by a annular flange provided at the end portion of said compartment to have an opening of larger diameter than said circular plug member for allowing said plug member to be thrust into said combustion chamber to open said passageway. 

1. A rocket carrying a payload for ejectment at a predetermined point along its trajectory comprising: a combustion chamber containing rocket propulsion fuel for propelling said rocket along a fixed path; a compartment attached to said chamber having one end nearest said combustion chamber filled with an explosive charge for supplying a rapid expanding force; shock reducing material positioned adjacent and in contact with said explosive charge for completely enclosing said explosive charge within an end portion of said chamber; communicating passageway concentric with said compartment and said combustion chamber; a circular plug member having a reduced diameter portion at one End to form a shoulder and a cavity at its other end, said plug member positioned between said chamber and said compartment and operable to open and close said communication passageway; a spring housed partially within the cavity in said circular plug and compressed in its closed position; and heat sensitive restraining collar fixably secured to said compartment and said plug at its reduced diameter portion for holding said plug member in a position to close said passageway; whereby the completed burning of the propulsion fuel in the combustion chamber causes hot gases to impinge upon the restraining collar allowing the passage of hot gases through the passageway to ignite the expelling charge to forcibly eject the payload from the compartment after the spring pressure overcomes the combustion chamber pressure.
 2. The rocket of claim 1 wherein said passageway is formed by a annular flange provided at the end portion of said compartment to have an opening of larger diameter than said circular plug member for allowing said plug member to be thrust into said combustion chamber to open said passageway. 